Magnetic circular dichroism spectra were obtained for [MOCl(4)](-) (M = Cr, Mo) and [WOCl4(H2O)](-) compounds. All of the spectra display temperature and field dependence consistent with a paramagnetic ground state. The two lowest energy bands are assigned to the d(xy) --> d(xz),d(yz) and d(xy) --> d(x2-y2) ligand field transitions. All of the compounds display vibronic structure on the d(xy) --> d(xz),d(yz) band arising from coupling with the totally symmetric M-O stretch. The third band is assigned to a b(1)(Cl) to b(2)(d(xy)) charge transfer transition and at slightly higher energies are charge transfer transitions from orbitals with e symmetry to the half-occupied d(xy) orbital. The low energy of the b(1) to b(2) charge transfer band provides a consistent explanation of the inverted EPR parameters found in these complexes and in molybdenum-containing hydroxylases.